Conventionally, a tire tester provided with a holding means for rotatably holding a tire and a simulated road surface formed on the outer periphery of a drum, endless belt or the like to ground the tire thereon is known. In this tire tester, the tire is rotated by rotating the drum, endless belt or the like by a drive means, whereby various performance tests are performed on the tire in a traveling state. Some tire testers of this type are configured so that the camber angle, slip angle and the like of the tire to the simulated road surface can be adjusted.
As such a tire tester, for example, a tire tester as shown in Patent Literature 1 is known, the tire tester comprising a frame which is moved up and down relative to a device body (hereinafter referred to as “lifting/lowering frame”) and a simulated road surface provided below this lifting/lowering frame. In this tire tester, a substantially A-shaped frame is mounted on the lifting/lowering frame so as to be horizontally turnable about a vertical axis drawn through a tread point of the tire. This substantially A-shaped frame can be angled (inclined) so as to be tilted transversely around an axis along a traveling direction of the simulated road surface. The substantially A-shaped frame (hereinafter referred to as “transversely tilted frame”) includes a spindle for rotatably supporting the tire.
Namely, in this tire tester, the tire can be grounded (pressed) on the simulated road surface or separated (lifted) from the simulated road surface by lifting and lowering the lifting/lowering frame relative to the simulated road surface which is moving in the horizontal direction. If the angle of the transversely tilted frame is changed on this occasion, the camber angle of the tire to the simulated road surface can be changed since the spindle (the rotational axis of the tire) is inclined thereby so as to cause a difference in height between both ends of its shaft center. Further, if the lifting/lowering frame is turned relative to the transversely tilted frame, the slip angle of the tire to the simulated road surface can be changed since the spindle is also turned (rotated as it is in the horizontal state).
In this tire tester, the spindle has a built-in sensor such as a load cell. Such a sensor can measure reactions or moments of the tire traveling at various camber angles or slip angles.